1. Technical Field
The present invention relates to a liquid ejection control device and the like which control a liquid ejection device ejecting a liquid in a pulsed state by using a piezoelectric element.
2. Related Art
There is a known technology in which a liquid is ejected in a pulsed state and an excision target is excised. Ejection of a pulsed liquid is a jet flow of the liquid which is ejected from a nozzle in a pulsating manner and will be appropriately referred to as “a pulsed liquid jet” in this specification.
There are various purposes of the pulsed liquid jet. For example, JP-A-2005-152127 discloses a proposed technology in which the pulsed liquid jet is utilized for a surgical operation in the medical field. In this case, the excision target is a living tissue, and the liquid is a physiological salt solution.
As a mechanism which generates a pulsed liquid jet, there is a known mechanism in which a piezoelectric element is used. In the mechanism, the piezoelectric element generates an instantaneous pressure in an operation fluid (a fluid) so as to cause a liquid to be ejected in a pulsed state by adding a drive voltage in a pulse wave shape to the piezoelectric element. Accordingly, when varying the strength of the pulsed liquid jet, the drive voltage applied to the piezoelectric element is controlled. Therefore, it is possible to consider a specification in which the strength of the pulsed liquid jet becomes variable by instructing a characteristic value of a drive voltage applied to the piezoelectric element, for example, the amplitude of a drive voltage waveform (which is a voltage amplitude and can also be referred to as the magnitude of a drive voltage) through an operation unit such as an operation dial or an operation button.
However, it is found that even though the characteristic value of the drive voltage to be instructed through the operation unit is changed, there may be a case where excisional circumstances such as the depth of excision and the volume of excision of the excision target cannot be changed as intended by a user. Detailed description will be given below. However, for example, it is found that even though a user changes the voltage amplitude twice, four times, ½, or ¼, the depth of excision and the volume of excision do not necessarily change in the same manner. When the pulsed liquid jet is used for the purpose of a surgical operation, it is not possible for an operator to obtain an operational effect in accordance with the feeling of the operation, thereby causing the possibility of a problem.
Meanwhile, when a cycle of ejecting a pulsed liquid jet is caused to be variable, the depth of excision and the volume of excision per unit time can be increased and reduced so that the velocity of excising the excision target becomes adjustable. However, the strength and the like of the pulsed liquid jet for one pulse can be changed based on the fact that when the cycle of ejection is changed, the shape of the drive voltage waveform changes. Therefore, there may be a case where the excision speed proportional to the frequency of ejection as intended by a user cannot be obtained even though the depth of excision and the volume of excision caused by the pulsed liquid jet for one pulse are changed before and after the cycle of ejection is changed, and the cycle of ejection is shortened, that is, the frequency of ejection is raised.
In addition, for example, in a case of the purpose of a surgical operation, a plurality types of liquid ejection devices in each of which an ejection tube portion where a liquid passes through has the shape, the length, the tube diameter, the material, the diameter of a nozzle, or the like different from each other are classified in accordance with the circumstances of a surgical operation, a resection site, or the like. Therefore, the depth of excision and the volume of excision caused by the pulsed liquid jet for one pulse can be changed in accordance with the type of the ejection tube portion of the liquid ejection device in use.